MULTI-DIRECTION TUNED MASS DAMPER WITH UNIQUE ASSEMBLY

AMORTISSEUR DE MASSE ACCORDE MULTI-DIRECTION A ENSEMBLE UNIQUE

English Abstract

A link assembly includes one or more mass damper assemblies. Each mass
damper assemblies include an annular mass disposed around the center rod of
the
link and an elastomeric bushing disposed between the center rod and the
annular
mass. This design for the mass damper assembly provides tuned damping in
multiple directions while simplifying the assembly of the mass damper assembly
to
the center rod.

Claims

CLAIMS

What is claimed is:

1. A link assembly comprising:
a center rod;
a fitting disposed at each end of the center rod;
a mass damper assembly attached to said center rod, the mass
damper assembly including an annular mass disposed around the center rod and
an
elastomeric bushing disposed between the center rod and the annular mass, the
mass damper assembly defining a first natural frequency in a first radial
direction
and a second natural frequency in a second radial direction, the first natural
frequency being different from the second natural frequency.

2. The link assembly according to Claim 1, wherein the elastomeric
bushing defines a first void between the center rod and the annular mass in
the first
radial direction.

3. The link assembly according to Claim 2, wherein the elastomeric
bushing defines a second void between the center rod and the annular mass.

4. The link assembly according to Claim 3, wherein the second void is
disposed opposite to the first void.

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5. The link assembly according to Claim 1, wherein the annular mass
defines a variable wall thickness circumferentially around the annular mass.

6. The link assembly according to Claim 5, wherein the elastomeric
bushing defines a first void between the center rod and the annular mass in
the first
radial direction.

7. The link assembly according to Claim 6, wherein the elastomeric
bushing defines a second void between the center rod and the annular mass.

8. The link assembly according to Claim 7, wherein the second void is
disposed opposite to the first void.

9. The link assembly according to Claim 1, wherein the annular mass
defines a first wall thickness in the first radial direction and a second wall
thickness
in the second radial direction, the first wall thickness being different than
the second
wall thickness.

10. The link assembly according to Claim 9, wherein the elastomeric
bushing defines a first void between the center rod and the annular mass in
the first
radial direction.

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11. The link assembly according to Claim 10, wherein the elastomeric
bushing defines a second void between the center rod and the annular mass.

12. The link assembly according to Claim 11, wherein the second void is
disposed opposite to the first void.

13. A mass damper assembly comprising:
an annular mass; and
an elastomeric bushing disposed within the annular mass, the
elastomeric bushing defining an aperture, the mass damper assembly defining a
first
natural frequency in a first radial direction and a second natural frequency
in a
second radial direction, the first natural frequency being different than the
second
natural frequency.

14. The link assembly according to Claim 13, wherein the elastomeric
bushing defines a first void between the aperture and the annular mass in the
first
radial direction.

15. The link assembly according to Claim 14, wherein the elastomeric
bushing defines a second void between the aperture and the annular mass.

16. The link assembly according to Claim 15, wherein the second void is
disposed opposite to the first void.

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17. The link assembly according to Claim 16, wherein the annular mass
defines a variable wall thickness circumferentially around the annular mass.

18. The link assembly according to Claim 17, wherein the elastomeric
bushing defines a first void between the center rod and the annular mass in
the first
radial direction.

19. The link assembly according to Claim 18, wherein the elastomeric
bushing defines a second void between the center rod and the annular mass.

20. The link assembly according to Claim 19, wherein the second void is
disposed opposite to the first void.

21. The link assembly according to Claim 13, wherein the annular mass
defines a first wall thickness in the first radial direction and a second wall
thickness
in the second radial direction, the first wall thickness being different than
the second
wall thickness.

22. The link assembly according to Claim 21, wherein the elastomeric
bushing defines a first void between the center rod and the annular mass in
the first
radial direction.

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23. The link assembly according to Claim 22, wherein the elastomeric
bushing defines a second void between the center rod and the annular mass.

24. The link assembly according to Claim 23, wherein the second void is
disposed opposite to the first void.

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Description

CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
MULTI-DIRECTION TUNED MASS DAMPER WITH UNIQUE ASSEMBLY
FIELD OF THE INVENTION
[0001] The present invention relates to a mass damper for an automotive
suspension. More particularly, the present invention relates to a multi-
directional
mass damper which is assembled to a component of an automotive suspension.
BACKGROUND OF THE INVENTION
[0002] As a type of vibration damping device for reducing vibrations of a
rod-shaped member, such as a shaft, a torque rod or a suspension link, used in
various suspension components, there is known a mass damper having a single
direction of tuned functionality. The single direction limitations of the
prior art
damping devices is due to their construction. Typically these prior art mass
dampers
consist of a rubber pad having a mass chemically bonded to one side of the
rubber
pad. A mounting bracket chemically bonded to the other side of the rubber pad
is
utilized to mount or attach the mass damper to the vibrating component. The
design
for the rubber pad and the mass are chosen to have a natural frequency that
corresponds to the natural frequency that needs to be damped.
[0003) One problem with the prior art mass dampers is that they are
limited to providing improved damping in only a single direction. When a
specific
application requires that vibration damping is required in multiple
directions, the only
option is to provide a separate single direction mass damper for each
direction that
requires damping.
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CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
SUMMARY OF THE INVENTION
[0004] The present invention provides the art with a multi-directional
damper which effectively dampens vibrations in multiple directions. The design
for
the multi-directional damper also provides for a unique and uncomplicated
method
for assembly, saving both time and money.
[0005] Further areas of applicability of the present invention will become
apparent from the detailed description provided hereinafter. It should be
understood
that the detailed description and specific examples, while indicating the
preferred
embodiment of the invention, are intended for purposes of illustration only
and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention will become more fully understood from the
detailed description and the accompanying drawings, wherein:
[0007] Figure 1 is a side view of a link assembly incorporating a mass
damper in accordance with the present invention;
[0008] Figure 2 is a plan view of the link assembly illustrated in Figure 1;
[0009] Figure 3 is an end view of one of the mass dampers illustrated in
Figures 1 and 2;
[0010] Figure 4 is a side cross-sectional view of the mass damper
illustrated in Figure 3;
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CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
[0011] Figure 5 is an end view similar to Figure 3 but illustrating a mass
damper in accordance with another embodiment of the invention;
[0012] Figure 6 is an end view of the other mass damper illustrated in
Figures 1 and 2; and
[0013] Figure 7 is a side cross-sectional view of the mass damper
illustrated in Figure 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014) The following description of the preferred embodiments) is merely
exemplary in nature and is in no way intended to limit the invention, its
application,
or uses.
[0015] There is illustrated in Figures 1 and 2 a link assembly 10 which
incorporates mass dampers in accordance with the present invention. Link
assembly 10 comprises a pair of fittings in the form of elastomeric bushing
assemblies 12, a solid or tubular center rod 14, a mass damper assembly 16 and
a
mass damper assembly 18.
[0016] Each elastomeric bushing assembly 12 comprises an eyelet 22, a
center connection fitting 24 and an elastomeric bushing 26 disposed between
eyelet
22 and center connection fitting 24. Each elastomeric bushing assembly 12 is
attached to an end of center rod 14 by welding or by other means known in the
art.
Link assembly 10 is connected between two components of a suspension system
utilizing the appropriate connectors and center connection fittings 24.
3


CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
[0017] Referring now to Figures 3 and 4, mass damper assembly 16 is
illustrated in greater detail. Mass damper assembly 16 comprises an outer
annular
mass 32 and an inner elastomeric bushing 34. The design for elastomeric
bushing
34 is chosen to damp a single specific frequency and it may include one or
more
annular cut outs 36 to tune it to the correct frequency. Elastomeric bushing
34 is
mechanically or chemically bonded to annular mass 32 and the size and design
for
mass 32 is also chosen based upon the natural frequency to be damped. While
annular mass 32 is illustrated as having a constant wall thickness, it is
within the
scope of the present invention to vary the wall thickness of the annular mass
to have
different frequency responses in specific radial directions as illustrated in
Figure 5.
(0018] Figure 5 illustrates a mass damper assembly 16' which comprises
outer mass 32' and inner elastomeric bushing 34. Elastomeric bushing 34 is
mechanically or chemically bonded to outer mass 32' similar to that described
above
for mass damper assembly 16. Mass damper assembly 16' is the same as mass
damper assembly 16 described above except for the replacement of outer mass 32
with outer mass 32'. Outer mass 32' is a multiple piece mass where the
individual
pieces are different sizes and thus different masses. Outer mass 32' has a
first
natural frequency in one radial direction and a different second natural
frequency in
a second radial direction which will dampen different frequencies in the
different
radial directions due to the variable sized multi-piece construction of outer
mass 32'.
While outer mass 32' is illustrated as a multiple piece mass, it is within the
scope of
the present invention to utilize a single piece mass 16' which includes the
different
wall thickness or masses arranged circumferentially around elastomeric bushing
34.
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CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
[0019] The assembly of mass damper assembly 16 or 16' is accomplished
by stretching the inner diameter of elastomeric bushing 34 and sliding the pre-

assembled mass damper assembly 16 or 16' onto center rod 14 prior to the
welding
of one or both of eyelets 22 of elastomeric bushing assemblies 12. Once
positioned
at the proper axial and circumferential position on center rod 14, mass damper
assembly 16 or 16' is held in position by mechanically or chemically bonding
elastomeric bushing 34 to center rod 14. The bonding of elastomeric bushing 34
to
center rod 14 removes the need for fasteners and/or bolted joints to attach
the mass
damper to the suspension link. Once the mass dampers have been bonded to
center rod 14, the assembly continues with the welding of the remaining
eyelets 22
and the assembly of elastomeric bushing assemblies 12.
[0020] Mass damper assembly 16 or 16' is capable of damping vibrations
in multiple radial directions and thus eliminates the need for having a
separate tuned
damper for each direction that requires additional damping.
[0021] Referring now to Figures 6 and 7, mass damper assembly 18 is
illustrated in greater detail. Mass damper assembly 18 comprises outer annular
mass 32 and an inner elastomeric bushing 134. Eiastomeric bushing 134 is the
same as elastomeric bushing 34 except that elastomeric bushing 134 includes
one
or more voids 136 to provide different frequency responses in specific radial
directions. The design for elastomeric bushing 134 is chosen to have a first
natural
frequency in a first radial direction and a different second natural frequency
in a
second radial direction to dampen a first specific frequency in the first
specific radial
direction due to the incorporation of voids 136 and a second specific
frequency in


CA 02511210 2005-06-30
Attorney Docket No. 1316C-000087
the second radial direction due to the elimination of voids 136. Elastomeric
bushing
134 is mechanically or chemically bonded to annular mass 32. While mass damper
assembly 18 is illustrated incorporating annular mass 32, it is within the
scope of the
present invention to incorporate annular mass 32' in place of annular mass 32.
This
design is illustrated in Figure 5 where voids 136 have been shown in phantom.
[0022] The assembly of mass damper assembly 18 is the same as that
described above for mass damper assembly 16 and once assembled, mass damper
assembly 18 is held in position by mechanically or chemically bonding
elastomeric
bushing 134 to center rod 14.
[0023] The description of the invention is merely exemplary in nature and,
thus, variations that do not depart from the gist of the invention are
intended to be
within the scope of the invention. Such variations are not to be regarded as a
departure from the spirit and scope of the invention.
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Representative Drawing